Chapter Demand 4 and Supply - University of North …traynham/ch04lecture.pdfAn increase in demand shifts the demand curve rightward, and a decrease in supply shifts the supply curve
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
1. Distinguish between quantity demanded and demand and explain what determines demand.
2. Distinguish between quantity supplied and supply and explain what determines supply.
3. Explain how demand and supply determine price and quantity in a market, and explain the effects of changes in demand and supply.
LECTURE TOPICS
<Demand
<Supply
<Market Equilibrium
COMPETITIVE MARKETS
A market is any arrangement that bring buyers and sellers together.
2
In this chapter, we study a competitive market that has so many buyers and so many sellers that no individual buyer or seller can influence the price.
COMPETITIVE MARKETS 4.1 DEMAND
Quantity demanded
The amount of a good, service, or resource that people are willing and able to buy during a specified period at a specified price.
The quantity demanded is an amount per unit of time. For example, the amount per day or per month.
4.1 DEMAND
<The Law of Demand
Other things remaining the same, • If the price of good rises, the quantity demanded
of that good decreases.• If the price of a good falls, the quantity
demanded of that good increases.
4.1 DEMAND
<Demand Schedule and Demand Curve
Demand
The relationship between the quantity demanded and the price of a good when all other influences on buying plans remain the same.
Demand is a list of quantities at different prices and is illustrated by the demand curve.
3
4.1 DEMAND
Demand scheduleA list of the quantities demanded at each different price when all the other influences on buying plans remain the same.
Demand curveA graph of the relationship between the quantity demanded of a good and its price when all other influences on buying plans remain the same.
4.1 DEMAND
4.1 DEMAND
<Individual Demand and Market Demand
Market demand
The sum of the demands of all the buyers in a market.
The market demand curve is the horizontal sum of the demand curves of all buyers in the market.
4.1 DEMAND
4
4.1 DEMAND
<Changes in Demand
Change in the quantity demanded
A change in the quantity of a good that people plan to buy that results from a change in the price of the good.
Change in demand
A change in the quantity that people plan to buy when any influence other than the price of the good changes.
4.1 DEMAND
Figure 4.3 showschanges in demand.
1. When demand decreases, the demand curve shifts leftward from D0 to D1.
2. When demand increases, the demand curve shifts rightward from D0 to D2.
4.1 DEMAND
The main influences on buying plans that change demand are:
• Prices of related goods
• Income
• Expectations
• Number of buyers
• Preferences
4.1 DEMAND
Prices of Related Goods
SubstituteA good that can be consumed in place of another good. For example, apples and oranges.
The demand for a good increases, if the price of one of its substitutes rises.The demand for a good decreases, if the price of one of its substitutes falls.
5
4.1 DEMAND
ComplementA good that is consumed with another good. Forexample, ice cream and fudge sauce.
The demand for a good increases, if the price ofone of its complements falls.The demand for a good decreases, if the price ofone of its complements rises.
4.1 DEMAND
Income
The demand for a normal good increases if income increases.
The demand for an inferior good decreases if income increases.
4.1 DEMAND
Expectations
Expected future income and expected future prices influence demand today.
For example, if the price of a computer is expected to fall next month, the demand for computers today decreases.
Number of Buyers
The greater the number of buyers in a market, the larger is the demand for any good.
4.1 DEMAND
Preferences
When preferences change, the demand for one item increases and the demand for another item (or items) decreases.
Preferences change when:• People become better informed• New goods become available.
6
4.1 DEMAND
<Demand: A Summary
4.2 SUPPLY
Quantity suppliedThe amount of a good, service, or resource that people are willing and able to sell during a specified period at a specified price.
The Law of Supply Other things remaining the same,
• If the price of a good rises, the quantity supplied of that good increases.
• If the price of a good falls, the quantity supplied of that good decreases.
4.2 SUPPLY
<Supply Schedule and Supply Curve
Supply
The relationship between the quantity supplied of a good and the price of the good when all other influences on selling plans remain the same.
Supply a list of quantities at different prices and is illustrated by the supply curve.
4.2 SUPPLY
Supply scheduleA list of the quantities supplied at each different price when all other influences on selling plans remains the same.
Supply curve
A graph of the relationship between the quantity supplied and the price when all other influences on selling plans remain the same.
7
4.2 SUPPLY 4.2 SUPPLY
<Individual Supply and Market Supply
Market supply
The sum of the supplies of all sellers in a market.
The market supply curve is the horizontal sum of the supply curves of all the sellers in the market.
4.2 SUPPLY 4.2 SUPPLY
<Changes in Supply
Change in quantity supplied
A change in the quantity of a good that suppliers plan to sell that results from a change in the price of the good.
Change in supply
A change in the quantity that suppliers plan to sell when any influence on selling plans other than the price of the good changes.
8
4.2 SUPPLY
2. When supply increases, the supply curve shifts rightward from S0 to S2.
1. When supply decreases, the supply curve shifts leftward from S0 to S1.
Figure 4.7 shows changes in supply.
4.2 SUPPLY 4.2 SUPPLY
The main influences on selling plans that change supply are:
• Prices of related goods
• Prices of resources and other Inputs
• Expectations
• Number of sellers
• Productivity
4.2 SUPPLY
Prices of Related Goods
A change in the price of one good can bring a change in the supply of another good.
Substitute in production
A good that can be produced in place of another good. For example, a truck and an SUV in an auto factory.
• The supply of a good increases if the price of one of its substitutes in production falls.
• The supply a good decreases if the price of one of its substitutes in production rises.
4.2 SUPPLY
Complement in production
A good that is produced along with another good. For example, straw is a complement in production of wheat.
• The supply of a good increases if the price of one of its complements in production rises.
• The supply a good decreases if the price of one of its complements in production falls.
9
4.2 SUPPLY
Prices of Resources and Other Inputs
Resource and input prices influence the cost of production. And the more it costs to produce a good, the smaller is the quantity supplied of that good.
Expectations
• Expectations about future prices influence supply.
• Expectations of future input prices also influence supply.
4.2 SUPPLY
Number of Sellers
The greater the number of sellers in a market, the larger is supply.
Productivity
Productivity is output per unit of input.
An increase in productivity lowers costs and increases supply.
4.2 SUPPLY
<Supply: A Summary
4.3 MARKET EQUILIBRIUM
Market equilibriumWhen the quantity demanded equals the quantity supplied—when buyers’ and sellers’ plans are consistent.
Equilibrium priceThe price at which the quantity demanded equals the quantity supplied.
Equilibrium quantityThe quantity bought and sold at the equilibrium price.